Apparatus and to form images of the straws of ferrous materials and nonferrous by means of a display magneto - optic

摘要

The invention relates to a process and apparatus for we shall now describe the cracks or straw 28 in a material 25. According to the invention, use is made of a layer of garnet magnetic epitaxial 20 filed on a non-magnetic substrate 10, the assembly being surrounded by a winding which generates a magnetic field in the garnet. The assembly is placed on the material 25 subjected to the test so that the magnetic field generated is disturbed by the presence of the straw, which causes a realignment fields magnetic in the garnet. It is projected through the garnet a bundle of application polarized 33, it is observed that the reflection by a surface reflective 22, interposed between the layer epitaxial and the material, through an analyzer 44 which detected the rotation of the polarization plane induced by the structure of the domains modified and thus makes it possible to visually observe the straw.